The invention relates to a filter or multicoupler which includes a resonator that can be electronically tuned by a tuning device and which has at least one tuning element, a switching element for selectively connecting the tuning element electrically to said resonator, and a control device for the switching element.
Some filters and multicouplers are already known. However, the known devices have proven unable to bring about simultaneously broad frequency tuning bands, high power functioning, very short electronic tuning time, and reduced insertion losses. The mounting between the different elements constituting a tuning device requires the soldering of contact wires, and their assembly is problematic, particularly because of the mechanical tolerances and thermal expansion between the different elements. These problems grow with an increase in the tuning frequency band and the number of tuning elements necessary for this purpose.
The present invention aims to propose an arrangement which palliates the disadvantages just stated.
In order to attain this goal, a tunable arrangement according to the invention has a coaxial resonator, of the quarter-wave type, with a central component constituting a line having a cylindrical shape with an upper surface for mounting of the tuning devices.
According to one aspect of the invention, the different elements constituting a tuning device which dissipate energy and have different thermal drain are mounted in a removable manner.
According to another aspect of the invention, the aforementioned elements are maintained in mechanical and electrical contact in the tuning device under the effect of pressure forces, advantageously a spring.
According to another aspect of the invention, a PIN diode and a tuning capacitor are mounted in series between an upper plate of the resonator and the body forming the line, the diode being attached in a removable manner by its casing to the upper plate and the tuning capacitor being attached in a removable manner to the body, and the two being electrically interconnected in series by a spring washer.
According to yet another aspect, the casing of the PIN diode has a threaded end piece intended for passing through the upper ground plate and is provided with a shoulder for resting against the internal surface of the plate under the squeezing effect of a nut screwed on the end piece on the other side of the plate.
According to yet another aspect of the invention, the tuning capacitor has a support provided with a threaded end piece which can be screwed into the upper surface of the body forming the line.
According to yet another aspect of the invention, the PIN diode rests on a frontal surface of a spring washer in contact with a support resting on the tuning capacitor.
According to yet another aspect of the invention, the tuning capacitor has a number of power capacitors connected in parallel and soldered in the aforementioned threaded support.
According to yet another aspect of the invention, the electrical contact between the control device for a PIN diode and the controlled PIN diode is formed by a contact element including a spring pin of which one end is connected to a choke coil of the control circuit while the other end is pressed under the effect of a spring against the aforementioned washer support.
According to yet another aspect of the invention, the upper surface for mounting of the tuning devices is suitable for mounting of a larger number of tuning devices than that which is strictly necessary for the production of the frequency increments, so as to increase the number of tuning increments, the maximum power or both.